How to pressure wash a driveway without damaging the concrete

Safety first: two ways a pressure washer can put you in the hospital

Injection injuries. A pressure washer stream can break skin and push water and debris deep into a hand or foot. Doctors treat high-pressure injection injuries as a medical emergency. The skin wound is often small, 1 to 7 mm, and the pain can seem mild, so people underestimate it^[4]. In one study, patients treated within 6 hours had fewer amputations than those treated later^[4]. If the spray breaks your skin, go to an emergency room right away and say it was a pressure washer injection. Never point the wand at a person or pet, and never clear the tip with your hand.

Carbon monoxide. Gas engines make carbon monoxide, which you cannot see or smell. CDC advises using gas-powered equipment outside, at least 20 feet away from doors, windows and vents^[5]. Do not run a gas pressure washer inside a garage, even with the door open, and keep it away from open windows while you wash.

Electric washers. Plug into a GFCI-protected outdoor outlet, keep the plug and cord out of puddles, and use only the cord length the maker allows.

Chemicals. Never mix cleaners. When bleach is mixed with ammonia it releases chloramine gas, which is toxic to breathe^[6]. Some concrete degreasers contain ammonia, so read every label before you add bleach to anything.

Pick the right nozzle and distance

Most damage comes from too narrow a tip held too close. HomeGuide's guidance^[1]:

Setting	What it does on concrete
40 degree tip	Gentle, wide spray for rinsing and sealed or decorative surfaces
25 degree tip	The usual starting point for driveways and walks
15 degree tip	Tough stains only, used briefly
0 degree tip	Can leave permanent lines in concrete; avoid on flatwork
Distance	Hold the tip 6 to 12 inches from the surface

A rotary surface cleaner attachment helps avoid the striped look that comes from sweeping a wand back and forth. HomeGuide lists rental at $20 to $40 per day^[1]. Professionals use commercial machines rated at 3,000 psi or more and 4 or more gallons per minute^[1], which is why their results look more even.

Step by step

1. Clear and sweep. Move cars and furniture, then sweep off leaves and grit^[1].
2. Check the surface. If the concrete is already flaking or scaling, high pressure can strip more of the weak top layer. See spalling, pitting and freeze-thaw damage first.
3. Pretreat stains. Apply a driveway cleaner and let it sit 5 to 10 minutes^[1]. Oil and rust need their own treatment; see removing oil and rust stains.
4. Wash in sections, working from the high side down so dirty water runs off the clean area^[1].
5. Rinse well to remove detergent residue, which can streak^[1].
6. Seal if you plan to. Let the slab dry first. See sealing concrete.

White, powdery deposits that come back after washing are often efflorescence, not dirt. Washing alone may not cure it; see efflorescence on concrete.

Pavers, stamped and sealed concrete need a lighter touch

Pavers, brick and stamped or decorative concrete need more care to avoid dislodging joint sand or stripping sealer, and pros often charge 10% to 25% more for them^[1]. Use a wider tip and more distance. Plan to re-sand paver joints after washing; see sealing and re-sanding pavers.

Where the dirty water goes

Wash water carries soap, oil and grime. Rules vary by city. In the Sacramento area, for example, local stormwater ordinances prohibit sending pressure-washing wastewater to the storm drain system, which they define to include gutters, streets and sidewalks^[7]. Before you use degreaser, check your city's stormwater rules, and block or redirect runoff onto a lawn where allowed.

What it costs

Source (date)	Typical price	Per sq ft
HomeGuide (Jun 2026)	$100 to $350 for a two-car driveway[1]	$0.08 to $0.35 cold water; $0.15 to $0.52 hot water[1]
Bob Vila, citing Angi (Jun 2024)	$100 to $350, about $210 average[2]	$0.20 to $0.40[2]
Fixr (Jan 2025)	$100 to $250 to power wash a 240 sq ft garage floor[3]	not listed

Many companies set a minimum charge of $75 to $150, and urban areas typically pay 15% to 30% more^[1]. Renting a machine yourself runs about $40 to $100 per day^[1].

When to call a pro

• The concrete is flaking, scaling or crumbling, where a pro can tell you if washing will make it worse or if repair comes first.
• Large driveways, stamped concrete or pavers, where a surface cleaner and the right pressure prevent stripes and lost joint sand.
• Heavy oil, rust or mold staining that needs chemical pretreatment and safe runoff control.
• Anyone without the right gear or experience: an independent contractor in your area carries the equipment and insurance.